Re: Anti-Freeze Flush: how to do at home
In my experience of owning cars (on my fifth), I used to perform a
flush with the prestone kit, but I always seemed to get a small leak
with the next year or two afterwards.
It is important to understand the function of coolant, to know why you
should change it.
The coolant actually serves 2 purposes, 1) to keep the system from
freezing and bump up the boil point a little, and 2) to keep the PH of
the coolant in the basic region (not acidic). The natural course of
the internal combustion engine eventually makes the mixture go acidic.
In fact the gylcol mixture will probably meet its thermal properties
for the life of the vehicle, however it is the PH that you should be
mostly concerned with.
Due to the coolant traveling across dissimilar metals, you get a
natural battery effect, which can lead to corrosion if your coolant
gets acidic (loss of basic salts such as K, Ca, and whatever else the
blend contains). In fact you can take a multimeter and place one lead
in the coolant and another lead on the engine ground and you will get
about 100mV (more or less depending on the PH). I no longer perform
flushes, since I feel that I dislodge more metal than I do good. And
if I need to use a flush to keep disloging loose metal, then I should
be more concerned with why my engine internals are corroding, not how
do I get rid of the particles.
My new method on my last two cars has been to drain whatever is in the
radiator (about one even gallon on 4cyl toyotas) every other year (or
30K miles) and add a fresh gallon of toyota red or pink coolant. They
claim the pink (super long life) can last 10 years, but I wouldn't
trust it to more than 5. The toyota red (long life coolant) is
claimed to last 5 years. So by my math, if I recharge half of the
cooling capacity in about half the suggested toyota interval, then, I
should always be within a safe margin of my coolant quality. In fact
the "American" green generally only stays within the PH for 2 years.
Some also contain silicates, which toyota is very adament about not
using. I think that the silicates are good for protecting metals
from corrosion or maybe it is for cavitation, however they are
abrasive and cause eventual seal damage and water pump failure.
You know how it is, everybody has an opinion and everybody thinks they
are right about there opinion. So this is my opinion for the time
being. I have used my method on a 97 camry with not a drop loss in
coolant at 130,000 miles. In fact the coolant system looks great -
very light contaminates. I am also using this method on an '03
corolla. I have a close friend who didn't change the american green
on a chrysler in 5 years and when they took it into service for a huge
coolant leak, they said the coolant was more rust than water. So they
wound up replacing the radiator and heater core. The engine wound up
dying about 2 years later with only 60K - blown head from overheating.
Thats,my two cents. Flushing the system isn't required if you address
the reason you have to perform the flush. However if you let the
system start to get out of control in the first place, then maybe a
flush would help remove some of the flow inhibiting particles. When I
drain the radiator, I have never seen an inclination of internal
breakdown, like I did when I let the cooling system go to the
recommended change interval on my previous vehicles.
By the way the prestone kit is simple and the direction are very
straightforward. All you need to due is trace the coolant plumbing. I
never did see a lot of contaminates when I did mine, not like when you
drain the hot water tank in your home or see a fire hydrant initially
flushed. It was more or less clear water. Personally I think
changing it is enough, unless it really looks bad, which you will know
when you open the petcock, since the contaminates tend to collect at
the bottom of the system. I would go with the same method you use on
the transmission fluid - drain old and add new. I think the flush is
a way for the service shops to charge you $50 for $10 worth of
coolant. They usually add the wrong kind anyways if you are a purist
to the toyota recommendations, since the green is the cheapest
available and the toyota red costs $20 for an undiluted gallon (which
translates to $21 for two gallons with $1added for a gallon of
distilled water). The toyota pink stuff is already diluted by the
way, so it is $20 mixed or twice as much with a claimed twice the
service length. It basically contains an additional additive
(sebacate or something). It leaves a pinkish/whitish powder whenever
it dries after spilt, which is probably more of those "super-salts". I
think all of the newer toyotas with aluminum blocks are using the
pink, but the older iron blocks used the red.
On Sun, 6 Nov 2005 10:05:25 -0500, [email]firstname.lastname@example.org[/email] (Ladd) wrote:
>I would like to flush out and renew the anti-freeze mixture (green) in
>my 1996 Camry station wagon (150,000 miles) and would like advice on how
>to do this properly at home.
>Here's what I'm guessing I could do, using a variation on the multiple
>drain/refill method I have used in the past for changing transmission
>Place pan under radiator.
>Take of radiator cap.
>Take cap off overflow tank.
>Set interior heater contol to "Hot"
>Open radiator drain valve (or remove bottom hose -- I haven't looked yet
>to see if there even IS a radiator drain valve)
>Allow all fluid to drain.
>Clean overflow tank either by tank removal or siphoning, then putting
>cap back on.
>Close radiator drain valve.
>Fill radiator with water from hose.
>Run engine for a minute or two to circulate water through the block,
>topping off if necessary.
>Repeat drain and refill a second and maybe a third time.
>For final refill use 50/50 mix of distilled water and anti-freeze.
>Fill overflow tank half-way with 50/50 mixture.
>Run engine for 15 minutes, adding cooling mixture to radiator as needed
>when air space appears. Also keeping eye on temp gauge for an overheat
>After air burps have ceased appearing, put radiator cap back on.
>Dispose of captured fluid properly and check radiator level after having
>driven a bit with cooling system under pressure (after letting cool a
>bit) and again later in the week for any slow-appearing air bubbles.
>Other than replacing the hoses (if soft or cracked) and/or clamps after
>the first drain and possibly the thermostat (which hasn't shown a
>problem to this point), am I doing something really wrong here?
>May I correctly assume that any major brand antifreeze from Costco or
>Wal-mart will work just fine? I have no idea what's in the radiator now,
>but it is definitely the green stuff...
>I have mixed feelings on doing a chemical flush. When doing routine
>maintenence and checking the radiator fluid levels I haven't noticed
>anything to indicate that the system has a corrosion issue, but it seems
>like a chemical flush has the possiblity of causing more problems than
>it might solve.